Alright, took another stab at it, but am not getting the right answers, because this method produces 31 MJ/kg for Hydrazine which is 50% too high.
That is almost certainly my fault. I gave you the wrong molecular formula for the hydrazine reaction. It should be
2N2H4 + N2O4 → 3N2 + 4H2O
Obviously the balance factor on the N
2 is inconsequential for thermochemistry, but it's still an error on my part. That's basic equation-balancing and I should have slowed down to check my work. And as long as I'm confessing error, the second equation should be
(CH3)2N2H2 + N2O4 → 4H2O + 2CO2 + 2N2
Again, inconsequential for thermochemistry but you can blame me for giving you incorrect information. I apologize. With the provisos I discuss below, your model should now give you results that seem more correct to you.
Haven't done this since college 32 years ago...
I assure you the laws of thermodynamics haven't changed.
...nor do I find it particularly interesting...
Irrelevant. It applies to your claim. Your claim is that (1) you observe the spacecraft in the video to rise according to a certain velocity profile, and (2) that this cannot be explained by the operation of a thermodynamic engine of a certain type and design. Why do you think you're obliged to supply suitable rigor for one leg of your claim but not the other? You initially went into a fair amount of detail on (1), even catching your own error. But your treatment of (2) has been to cite one parameter of rocketry and largely dismiss all other discussion with what amounts to yelling "Nuh-
unh!" and shifting the burden of proof.
In order to expect your claim to be taken seriously and establish you as the next Edward Snowden, you are obliged to demonstrate that your grasp of thermodynamic engines is sufficient for you to show that (2) is sufficiently predicated—not just according to what you find interesting, but according to what laws of physics apply. Failing that, you are obliged to demonstrate that you understand enough about the foundational principles to apprehend an answer provided by someone else. You managed to find your way to the first law of thermodynamics—good. And after some false starts, you have managed to home in on a defensible method for ascertaining the enthalpy we have to work with. It's clear neither of us should be taking any shortcuts. Until we get there, the more parsimonious explanation for (1) remains that there is a physical effect at work that isn't being properly considered, not that vast amounts of effort went into perpetrating a hoax.
You seem to have adopted this very weird argument from silence that says if
other people can't satisfy your (2), you can stand on leg (1) without any further demonstration. Why you think you're allowed to establish rigor for only half your argument beggars belief.
...especially since the value I seek should already be well-known, via real-world testing.
Then why couldn't
you just look it up? It may surprise you, but there is no
Big Book of Answers that you can simply look up whatever question might pop into your head. First, calorimetry is not a slam-dunk. It's very hard to do correctly, which is why a lot of the commonly used numbers are remeasured every few decades. Second, calorimetry is dangerous, especially with high-energy, hard-to-handle substances like these fuels. Third, we don't have to perform literally every conceivable chemical reaction and measure it under every set of circumstances in order to figure out what we're doing. Analytical thermochemistry still exists because we still need it.
Your claim that you don't think I'd believe you if you state the A50 Heat of Combustion is non-credible.
I just gave you a good reason not to trust me—I might make a mistake. Had I simply handed you a number, you might have just used it without wondering how it was arrived at, or without having any way of catching my error. This is why we go step by step, in lock-step, and show the work.
Imagine an alternate universe where you asked me for some quantitative estimates for these non-canonical effects way back on, say, page 5, and I just gave you some figure out of the blue that just magically made up for all of it and declared victory. Can you honestly say you wouldn't have questioned where any of those numbers came from? Would you have said, "Oh, okay, I guess those numbers plucked out of thin air really put me in my place—thanks!" No, you would have asked me to show my work, and I'm sure there would have been a lively debate over whether that work was valid or not. The problem with that up-front approach is that before we disabused you of a few of your misconceptions you simply threw out a bunch of simplistic knee-jerk objections as if they somehow settled the issue no matter how robust the explanation. And you're still trying to do that. You still want to believe there's just some easy look-up that means you don't have to rise to your burden of proof.
Please move this along.
Asked and answered.
People are waiting for you to show us where you are headed with all of this.
Who are you speaking for?
If you had paid more attention to the questions I asked previously, you would have a pretty good idea where we're heading. You invoked the first law of thermodynamics and are homing in on a value for how much enthalpy is in the system. But those are for a given set of conditions. I asked you some questions intended to discover to what extent we can believe those conditions hold. And if they don't, what should change? For example, you used the heats of formation for the liquid phase for the propellants. Is that the right answer under all the conditions that apply to our problem? Why or why not? This is why we still do whiteboard thermochemstry. There's no one number that works in all cases.
Once we have a properly framed idea of the enthalpy in a thermodynamic engine, the next step is to reason carefully about how that can be harnessed to do work. As before, there's a simplistic model that holds for some standard, ongoing conditions. And then—since this is a non-canonical portion of the engine's operation—we might have to think of ways to reason about those nonstandard conditions.
